This is true. Future techs only increase your score slightly, whereas if you diverted the money into luxuries, the extra happiness would probably more than make up the same score increase.
Or, if you are going for any type of victory condition, just taking the extra cash could come in extremely handy in rush-buying units or improvements.
By this point in the game, you should know whether you are close to winning or not, so you can decide.
The only reason to research them IMHO is if you are looking for a histograph win, and your citizens are pretty much completely happy. Then a few extra points from techs might help. However, my games usually finish before the Modern Ages are over, so i can't tell you how many extra points you'll get.